Conference noted::bicycle

    
    A number of perhaps not-very-useful thoughts come to mind:
    
      - Shouldn't the chain just fall off the small chainring?
        Why does it in effect get sucked in next to the chain stay?
        When other people's chains fall off, they just drag on the ground.
    
      - Does anyone have experience with the Rohloff?  You could try
        (a cheap experiment!!) a Sedisport, just to see if that makes
        any difference.
    
      - What kind of gear-shifts are you doing when this happens?
        Are you double shifting?  Is there a lot of chain angle?
        (For example, small rear cog, small chain ring?)  A lot of
        chain slop?  (Is the chain taut enough?)
    
      - Can't you just carry an 8mm or whatever size Allen key to
        undo a Chorus crank?  (I know, this is not a solution to the
        chain's falling off.)
    
      - Does the chain fall off when you shift or randomly as you
        pedal along?  If the former, is the front derailleur's travel
        limitation set correctly?
    
    -john

    
    	If your front derailleur limit screws are okay,  you might check
    the height of the whole derailleur itself on the seat tube.  Looking
    at it from the drive side of the crank, the derailleur should clear
    the top of the big ring by 1-1.5 mm (according to Shimano specs).
    	Looking down from the top, the outside edge of the front derailleur
    should run parallel to the big ring's edge.  This is not as easy to
    accomplish as you'd think...
    	If that doesn't work, check the specs.  It is possible that the
    derailleur is not designed to handle the disparity in the number
    of total teeth, front AND rear.
    
    Other possibilities:  chain is worn out, chain is too long or mis-
                          aligned?
    
     2
    r

    don't shift.
    
    ed

     I've  got a Rohloff - They're (from what I understand) targeted at the
    new Campy 8spd config... My guess is (if it is the chain) you could
    save big dough by going with a cheaper chain. 
    
     That is a strange problem, though. I have no problems with my stuff.
    
        Chip

    seriously though, I think it's part of the Chorus design.  Others
    either leave so much space between the spider and the bb that the
    chain can't get jammed or they leave so little that it can't fit.
    
    Ah-hah, grind/file away part of the spider!
    
    ed

     This is a stupid question I know, but is the spindle in correctly?
    
        Chip

    Thanks for the response so far....
    
    I think I will try shortening the chain a little as it may be a bit
    too slack and maybe take the bike into the local LOOK/campy dealer to check
    the spindle etc. The chain very rarely jumps off and the jam occurs if
    I momentarily continue pedalling after the chain is off. It may also be
    the big jump from 53 to 39 that causes it to come off. Has anyone seen
    that with 14speed and 53/39 combinations??
    
    -steve- 

RE: .7

    I've got a fairly new Schwinn Paramount Series 3 road bike which does
    a similar thing.  Sometimes when I'm changing from the 53 to the 42 and
    I'm spinning fast, the chain gets jammed next to the chainstay for
    just a second, then pops back.  It does a number on the paint, not to
    mention my rythm.

    I, too was wondering if my chain was too long and had too much slack.
    I'm pretty sure my limit screws are set properly - It shifts fine each
    way and doesn't rub the chainring except when I crank it on in the next
    to smallest cog (while on the small front ring).

    If you shorten your chain, please let us know the results.

-Buddy

     A 39 to 53 jump should not be a problem. It will require a finer tuned
    adjustment, but should work fine if everything else is set up
    correctly, e.g. front derailleur, chain alignment, etc...
    
        Chip 

    If you look at the Performance catalog, the specs show what kind
    of load (no. of teeth) the fron deraileurs are designed to handle.
    
    I have a friend has a 53-39 Ultegra that must be shifted gently
    or it will jump off.  Ultegra is not _supposed_ to handle that load.
    That was the source of his troubles.  I, on the other hand, have been
    very lucky with my Dura-Ace.  Even when my limit screws are too open,
    I can't roll roll the chain off to the inside.
    
     2
    r

    I use a 39-53 Dura-Ace up front.  Last year I had some problems with 
    the chain rolling off at both extremes.  This year I simply spent more
    time with all adjustments and don't have any problems even with quick
    hard shifts.
    
    Bob

    I've got 52-38 at the front and no problems whatsoever with a standard
    Shimano 105SC front changer. 
    
    
    Rod

I'm running a 39/53 with Ultegra STI, with no problems, even with very fast
double shifts.